Invention of magnetic resonance imaging

Insights into the human body

Over the past three decades, magnetic resonance imaging (MRI) has developed into a unique tool for both scientific research and medical diagnosis. MRI generates pictures from inside the body of humans or animals that not only demonstrate the exact status of the inner organs, but even visualize their functions. Particular advantages are the access to high spatial resolution and the availability of endogenous soft-tissue contrasts that allow for an excellent sensitivity in the detection of pathologic alterations. Moreover, to the best of our knowledge, MRI is completely harmless for the organism, as it does not rely on the use of ionizing radiation ­ in contrast to X-ray computed tomography. MRI can therefore be applied as often as necessary without risk for the patient. Altogether, these features render MRI an indispensable diagnostic modality in today¹s medicine considerably expanding classical X-ray techniques. Magnetic resonance imaging was invented in 1972 by the American chemist Prof. PauI C. Lauterbur. In the prestigous scientific journal NATURE he described the basic principle for generating Images using magnetic resonance signals of atoms: These signals are emitted from atomic nuclei if they are exposed to a strong static magnetic field and an additional electromagnetic field. The strengths and frequencies of the magnetic resonance signals contain information about the atoms¹ neighborhood. Known as magnetic resonance spectroscopy since 1946, these properties are widely exploited for the elucidation of molecular structures in physics and chemistry. Beyond these ideas Prof. Lauterbur for the first time succeeded in the development of a principle which allows for a spatial discrimination of magnetic resonance signals. This was achieved by a combination of the basic experiment with additional spatially distinct magnetic fields, a technical procedure for the variable spatial encoding of a sufficiently large number of magnetic resonance signals, and a mechanism for the reconstruction of an image.

Already in his first publication Paul Lauterbur envisioned future applications that have been fully used and implemented only recently. He not only detailed the mechanisms underlying imaging and showed first experimental results, but also mentioned novel possibilities based on paramagnetic MRI contrast agents. In addition, he proposed to simultaneously record the chemical and spatial information in order to noninvasively monitor metabolic processes within the living body. The seminal work of Prof. Lauterbur, originally denominated as “zeugmatography”, has enabled and inspired a rapid and pronounced technical and scientific development. Current applications range from basic biologic research to a major role in clinical medicine. In fact, MRI is now considered to represent the most important modality in diagnostic imaging. Lauterbur has initiated and driven these developments and apart from the original invention continued to make important contributions. Today, MRI yields three-dimensional maps of complex organs and visualizations of complete body regions. Various technical approaches allow for an accurate delineation of organs or dynamic recordings of the beating heart or even the determination of blood flow velocities within selected vessels.Without doubt, the diagnostic procedures within most hospitals are no longer imaginable without magnetic resonance imaging.

In recent years Lauterbur worked on the development of a magnetic resonance microscope in order to provide extreme spatial resolution for the physiologic analysis of very small structures such as single biologic cells. Another area of research were new MRI approaches to investigate the function of the brain and related illnesses. Recently, Paul Lauterbur has started a program to study prebiotic molecules: chemical forms considered to be involved in the origin of life. Prof. Paul C. Lauterbur is honored with the Eduard Rhein Award for his fundamental work leading to the invention and development of magnetic resonance imaging.

Dr. Sönke Mehrgardt,
Infineon Technologies